Conventionally, a card reader structured to read magnetic data recorded on a card has been known (see, for example, Patent Literature 1). A card reader described in Patent Literature 1 includes a magnetic head for reading magnetic data recorded on a card. Further, the card reader includes a pre-head (magnetic head) for detecting whether magnetic data are recorded in a magnetic stripe of a card inserted into a card insertion port or not.
In an industry where a card reader is utilized, illegal acquisition of a signal outputted from a pre-head by a criminal who illegally acquires magnetic information recorded in a card, so-called “tapping” has conventionally become a large issue. In the card reader described in Patent Literature 1, a false signal output circuit structured to output a signal different from the signal corresponding to magnetic data recorded in a card is provided in an inside of the pre-head and thus, even when a criminal acquires a signal outputted from the pre-head, the criminal is unable to acquire a signal corresponding to magnetic data recorded in the card. Therefore, in the card reader, illegal acquisition of magnetic information by a criminal is prevented.